A Convenient and Efficient Synthesis of Naphthazarin

Peng, Ying; Zhou, Wen; Zhang, Min; Wang, Chengdong; Chen, Qian; Jiang, Shengjie; Li, Shaoshun

doi:10.3184/174751911x12964930076669

Cited by 3 publications

(2 citation statements)

References 20 publications

(21 reference statements)

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“…Hydrazide-hydrazone Schiff bases are the class of compounds with an azomethine ( N CH ) active pharmacophore and have significant biological activities. This class of compounds has been reported to exhibit diverse biological activities, such as, antimicrobial, 1 antioxidant, 2 anticancer, 3 antitubercular, 4 anticonvulsant, 5 anti-inflammatory, 6 antifungal, 7 antiviral, 8 and antibacterial 9 activities. Recently, Ayman et al 10 described the pro-angiogenic and anticancer activities of Schiff bases of N-valproyl-4-aminobenzoyl hydrazide.…”

Section: Introductionmentioning

confidence: 99%

Quantum‐Chemical Studies to Approach the Antioxidant Mechanism of Nonphenolic Hydrazone Schiff Base Analogs: Synthesis, Molecular Structure, Hirshfeld and Density Functional Theory Analyses

Alam

Lee

2015

Bulletin Korean Chem Soc

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In the present study, five nonphenolic (E)‐N′‐benzylidenebenzohydrazides including three new compounds were synthesized and evaluated for their free radical scavenging activities using 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH). X‐Ray analysis of a single crystal of (E)‐N′‐(4‐chlorobenzylidene)benzohydrazide (3c) revealed a triclinic, space group P‐1 structure with a trans configuration around the azomethine (C2N2) double bond. The three‐dimensional Hirshfeld surfaces and the related two‐dimensional fingerprint plots were also drawn to study the plausible intermolecular interactions. Density functional calculations of structures, electronic densities, frontier molecular orbitals modeling, and Mulliken charge analysis of all compounds were performed at the B3LYP/6‐311G level of theory. Theoretical vibrational frequencies were predicted and compared with experimental values, and results supported the validity of optimized geometry of noncrystalline compounds. All synthesized compounds showed significant DPPH radical scavenging activity, although compound 3d exhibited greatest antioxidant activity with an IC50 value of 11 μM. The results of DFT analysis were used to explain the proposed antioxidant mechanism of (E)‐N′‐benzylidenebenzohydrazide analogs. This analysis revealed that protons attached to N, O, and C atoms possessing high negative charge are involved in the production of free radicals that scavenge DPPH. Moreover, the antioxidant activities of (E)‐N′‐benzylidenebenzohydrazide analogs correlated well with HOMO–LUMO energy difference of molecules.

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Section: Introductionmentioning

confidence: 99%

Quantum‐Chemical Studies to Approach the Antioxidant Mechanism of Nonphenolic Hydrazone Schiff Base Analogs: Synthesis, Molecular Structure, Hirshfeld and Density Functional Theory Analyses

Alam

Lee

2015

Bulletin Korean Chem Soc

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“…1 Shikonin (SK) and its closely related derivatives, isolated from the root of Lithospermum erythrorhizon., have attracted much attention in view of their interesting antitumor activities. [2][3][4][5][6][7][8] Many shikonin derivatives showed potential as cancer inhibitory agents in cell culture studies, but did not performed well in vivo, possibly because of their extensively bioreductive alkylation with nucleophiles such as glutathione, proteins or DNA. [9][10][11] Prior results indicate that the dimethylation of the naphthazarin ring may benefit the antitumor activity of quinines.…”

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confidence: 99%

A Partial Synthesis of 5,8-O-Dimethylshikonin and 6-Isomer of 5,8-O-Dimethylshikonin

Zheng

Wang

Zhu

et al. 2011

Journal of Chemical Research

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A convenient synthesis of 5, 8-O-dimethylshikonin and the 6-isomer of 5,8-O-dimethylshikonin was developed in 81.8% total yield from shikonin. (R)-4-Methyl-1-(1,4,5,8-tetramethoxynaphthalen-2-yl)pent-3-en-1-ol was prepared in a one-pot two-step approach and then oxidised with ceric ammonium nitrate. This is simpler and the overall yield is higher than previous methods. The reaction conditions are milder and more environmentally friendly to environment, avoiding the use of the toxic and expensive reagents methyl iodide and chloromethyl ether and are more applicable to large-scale preparation. This is important because shikonin and its closely related derivatives have attracted much attention in view of their antitumor activities.

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